Brief Introduction to SWIMS

Simultaneous-color Wide-field Infrared Multi-object Spectrograph, or SWIMS, is capable of


SWIMSComponent Assembly

Instrument Papers


Detector Control

Multi-Object Spectroscopy Unit (MOSU)

Integral Field Spectroscopy Unit (IFU)

Field of Views

Field of view (FoV) of the telescope is covered with multiple HAWAII-2RG arrays (λ_{cut}=2.5 μm, ∼ 0.2-mm or ∼ 10-pixel gap between arrays).

Imag. FoVφ9.6' (∼ 8.6' × 8.6')6.6' × 3.3'
Spec. FoV3.7' × 8.6'2.8' × 3.3'
# of arrays per arm4
(4096 × 4096 pixles)
(4096 × 2048 pixels)
Pixel scale (arcsec/pix)0.1260.095
Array configurationfov_blue_tao.png

Light-shaded regions show the FoV for the imaging mode while dark-shaded regions for the spectroscopy mode (for full range of spectra).

Black dots represent positions of source in the imaging mode which are also equivalent to the spectral positions of undeviated wavelength (λ ∼ 1.027 μm for blue, ∼ 1.734 μm for red).

Each stripe indicates the full range of the spectrum obtained (from shorter on the left to longer wavelength on the right). Note that any optical aberrations are not considered which would make the spectrum slightly broaden.

Available filters/grisms

Blue (0.9-1.4 μm)Red (1.4-2.5 μm)
Broad-bandY (λc=1.027, Δλ=0.096 : fileplot), J (1.251, 0.167 : fileplot)H (1.644, 0.291 : fileplot), Ks (2.139, 0.313 : fileplot)
Medium-bandJ1 (1.174, 0.118 : fileplot), J2 (1.294, 0.123 : fileplot)H1 (1.502, 0.121 : fileplot), H2 (1.617, 0.116 : fileplot), H3 (1.735, 0.117 : fileplot), K1 (2.023, 0.138 : fileplot), K2 (2.170, 0.140 : fileplot), K3 (2.314, 0.128 : fileplot)
Narrow-bandNB1244# (1.244, 0.015 : fileplot), NB1261# (1.261, 0.016 : fileplot), Paβ (1.294, 0.038 : fileplot), Paβ-off (1.329, 0.033 : fileplot)NB1630# (1.630, 0.017 : fileplot), NB1653# (1.652, 0.016 : fileplot), Paα (1.876, 0.022 : fileplot), Paα-off (1.948, 0.036 : fileplot), NB2137# (2.133, 0.021 : fileplot), NB2167# (2.164, 0.022 : fileplot)
GrismzJ (2.40 Å/pix, R ∼ 700-1200 w/ 0.5" slit)HKs (4.57 Å/pix, R ∼ 600-1000 w/ 0.5" slit)

Filters followed by "#" are those for SWIMS-18 survey. Requests for use for any other purpose will be also welcomed.

Transmission curves

ASCII data for each filter transmittance :

Integral Field Spectroscopy Unit

A compact & lightweight image-slicer IFU will be installed into the MOSU cryogenic storage.

Note that the following parameters may be subject to be changed.

λ (μm)0.9-1.4 (blue) & 1.4-2.5 (red)
R (=λ/Δλ)900-1400 (blue), 700-1200 (red)
FoV18.4" × 13.7"14.0" × 5.2"
# of slice2613
Slice width0.5"0.4"

Multi-object Spectroscopy Unit

The cryogenic storage called the carousel have 23 slots for night observations. Of them, several kinds of engineering-use masks and long-slit masks (one slot each), and one IFU module (occupying two slots) will be exclusively assigned. Other (∼ 15) slots can be used for users' MOS masks.

The time required to exchange from one mask to another is about 2.5 minutes (and additional 5 seconds/slot to rotate the carousel). The time for target acquisition will be measured on the telescope during engineering nights.

Detector Performance

We utilize an ASIC, called SIDECAR, and its interface board, JADE-2, which control all of readout functions, to efficiently operate Teledyne HAWAII-2RG 2048 × 2048 HgCdTe infrared array.

Under cryogenic condition (∼ 77K), the detector performance has been assessed, as listed below.

Minimum Exposure Time1.48 sec
Dark Current< 0.05 e-/sec/pix
Readout Noise∼ 20--25 e- (CDS)
∼ 3--5 e- (32 Fowler)

Integrated performance (e.g., simulateneous control of multiple arrays, influences of other peripherals on readout noise, etc.) is currently being investigated.


Total throughput including the telescope is estimated to be ∼ 0.4 for imaging and ∼ 0.3 for spectroscopy.

Expected sensitivities (AB mag) on the Subaru telescope are calculated with assumptions of seeing size=0.5 arcsec (photometry aperture radius=0.5 arcsec for point source or spatial extent=5.0 arcsec for extended source), exposure time=1 hr, and S/N=5.

Sensitivities on the TAO 6.5-m telescope are supposed to be ∼ 0.3 mag shallower due to smaller light-collecting area.

Note that these values may change according to the background conditions of OH airglow and thermal emission.

Current Status

Coming soon.

Development Timeline

Coming soon.


添付ファイル: fileswimslognote_20201002.xls 343件 [詳細] fileswimslognote_20180606.xls 313件 [詳細] fileswims-y.jpg 481件 [詳細] fileswims-nb1244.jpg 471件 [詳細] fileswims-nb1292.jpg 457件 [詳細] fileswims-nb1326.jpg 453件 [詳細] fileswims-filter.jpg 202件 [詳細] fileswims-nb1261.jpg 469件 [詳細] fileswims-h2.jpg 416件 [詳細] fileswims-j.jpg 468件 [詳細] fileswims-mbfilter.jpg 242件 [詳細] fileswims-j2.jpg 427件 [詳細] fileswims-nb1653.jpg 440件 [詳細] fileswims-h3.jpg 437件 [詳細] fileswims-k3.jpg 473件 [詳細] fileswims-nb1875.jpg 426件 [詳細] fileswims-k1.jpg 443件 [詳細] fileswims-nb2137.jpg 428件 [詳細] fileswims-j1.jpg 447件 [詳細] fileswims-h1.jpg 473件 [詳細] fileswims-k2.jpg 416件 [詳細] fileswims-nb2167.jpg 434件 [詳細] fileswims-nb1945.jpg 506件 [詳細] fileswims-h.jpg 424件 [詳細] fileswims-ks.jpg 456件 [詳細] fileswims-nb1630.jpg 450件 [詳細] 333件 [詳細]

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Last-modified: 2021-04-05 (月) 13:44:51